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Author Topic:   Classic 15-footer with 50-HP

LKD posted 03-01-2011 07:19 PM ET (US)
I know the classic 15-foot Boston Whaler boat is rated for a maximum 70-HP engine, but is a 50-HP Yamaha considered to be adequate power for this hull? I value and appreciate all responses. Thanks--Keith
Russ 13 posted 03-01-2011 07:26 PM ET (US)
It depends what your primary use of the boat will be. For general use, with two to three passengers, yes the 50-HP will be fine. If you want to waterski and pull inflateables then 70-HP or 90-HP would be the way to go. I have a 90-HP on a 1989 hull that is SUPER, but I use the boat to tow wakeboards and tubes. The 15-footer is a great little boat.
Jeff posted 03-01-2011 07:44 PM ET (US)
Growing up we had a Super Sport 15 with a four-cylinder Mercury 75-HP on it. The boat was beyond what would be considered safely powered. It was a rocket that needed your utmost attention at speeds above 35-MPH as the hull had a real tendency to chine walk. It would top out with just me at speeds in the 50-MPH range, which was way too fast. That ended up being the reason my father sold it. Nonetheless, if I had one today I would prefer it to be powered with a 50-HP or may 60-HP motor. I honestly think that is enough power for that hull even if you are wanting to do water sports with it. This is coming from a guy who usually advocates for powering beyond the recommended max.
BobL posted 03-01-2011 10:02 PM ET (US)
Keith--I have a 1987 Super Sport 15 with a two-cycle Yamaha 50-HP. I think that a 50-HP outboard is plenty for the boat. It is fast, pops up on plane quickly, and top speed is as fast as I need. My wife and I usually just use the boat for cruising around. Part of what makes this combination handle so well is the lightweight engine. With power tilt and trim it weighs about 165-lbs. Unless you plan to really load up the boat and use it for water sport, I think you will be happy with the performance and economy of a 50.
BobL
pcrussell50 posted 03-01-2011 11:03 PM ET (US)
I have the max power engine option on my Sport 13, 40-HP and it accelerates like a R-O-C-K-E-T-S-H-I-P. I can't even come close to full throttle in the ocean. I say, if you're an ocean boater, you'll be fine with the 50. If you will have access to smooth water and want to be a fast boater, you'll want the 70, because you'll be able to get well into the upper 40's if you rig right and don't put too much heavy stuff. It's probably the "fastest" hull in the Whaler lineup.
-Perer
andrey320 posted 03-01-2011 11:26 PM ET (US)
I agree with Peter. I've got a 50 Honda on my Dauntless 15 and it is not a fast boat by any means, but I can't go over 25mph for long most of the time anyway. My boat tops out at a bit over 30mph. The Dauntless is a much heavier hull too, so a sport would go several miles faster than that. My boat with a few people on board pulls me (160 lbs) out of the water on a wakeboard with ease.
kwik_wurk posted 03-02-2011 12:57 AM ET (US)
For average use, a 15 with 50-HP would be great. Inner tubing would be fine, even wake boarding. But, I wouldn't water ski behind it. - And if you have kids it's not overpowered.
A 15 with a 90 Mercury is a rocket ride. My friends had one in high school and we could pop wheelies and jump freighter wakes--way overpowered for our level of common sense. And it would yank you right out water skiing. However the boat is a little light and you could really pull it around when cutting hard.
The only thing we didn't like was the boat sat a little squat in the back with the over sized engine.
pcrussell50 posted 03-02-2011 02:31 AM ET (US)

quote:
The only thing we didn't like was the boat sat a little squat in the back with the over sized engine.
Like pretty much all fast, outboard powered, v-hull boats.
-Peter
Peter posted 03-02-2011 06:51 AM ET (US)
A 50 HP outboard on a classic 15 Whaler should be able to push it to 36-37 MPH, which is pretty fast. A 70 will push it to at least 42 MPH. Over 39 MPH the boat has a tendency to chine walk and requires more concentration in driving it.
jimh posted 03-02-2011 07:46 AM ET (US)
[Moved to PERFORMANCE.]
jimh posted 03-02-2011 08:02 AM ET (US)
I had a SPORT 15 with a 50-HP Mercury. It would hit about 35-MPH at full throttle. It was a very fun and responsive boat.
elaelap posted 03-02-2011 09:23 AM ET (US)
My Yamaha F60 pushed my Sport 15 center console along at ~42 mph with only me aboard. Don't know about waterskiing or wakeboarding, though...never had the pleasure.
http://continuouswave.com/ubb/Forum1/HTML/018267.html
Tuco
weekendwarrior posted 03-02-2011 10:02 AM ET (US)
I have a 50HP Honda on my Montauk 17' and it's fine. Top speed just a tad over 30mph, fine for wakeboarding even with 5 in the boat. Not really enough to pull a tube with any excitement but fine for dragging little kids around. I did pull a girl on a slolem (sp?) ski once, she got right up but I was pretty much full throttle to give her enough speed and she didn't really do much in the way of tricks. So in short, 50HP is plenty practical for the 17 for most uses, I think it should do fine on a 15.
Tohsgib posted 03-02-2011 10:20 AM ET (US)
I have had a couple 15's and a 50 is plenty for most people and you can pull a skier with one. Mine did about 37mph which is flying when you are 9" above the water. You can also run all day on a 6 gal tank. For years I ran my 79 sport with a 1984 Johnson 60 which would run a 19" SST @6k through a 2.4:1 which is the same as the 70...she flew but way before the GPS days.
dgoodhue posted 03-02-2011 10:24 AM ET (US)
If setup properly you should see top speed of around 36mph or not all that much different than a max hp classic 13. I would guess it will be a touch slower on acceleration than the max hp 13' because of the extra weight of the hull.
dgoodhue posted 03-02-2011 10:27 AM ET (US)

quote:
It's probably the "fastest" hull in the Whaler lineup.

It's one of the faster small Whaler hulls.
Peter posted 03-02-2011 11:24 AM ET (US)
I think the classic 15 hull is faster than the classic 13 hull. The 13 has a hook in the hull and drags skegs through the water, the 15 does not. It would not surprise me in the least to find out that the 15 goes faster with a 40 HP motor than the 13 does.
pcrussell50 posted 03-02-2011 11:49 AM ET (US)

quote:
It's one of the faster small Whaler hulls.
I put "fastest" in quotes, because I was using the word to refer to the hull bottom shape, not necessarily the top speed attained. The 15's bottom looks almost like a proper performance boat, minus the pad.
-Peter
Tohsgib posted 03-02-2011 12:02 PM ET (US)
Been discussed before and I belive the 15 is the fastest Whaler in proportion to size. The 15 is just as fast if not faster than a 13 with comparable power and hence why the new 130 Sport does so well even weighing more than a classic 15.
mkelly posted 07-10-2012 12:02 AM ET (US)
I realize this thread is old & may not be read....but I recently repowered my 1986 15' center console sport (I think that's the model) with a 60 HP Yamaha 4-stroke...it is awesome! Highly recommend the Suzuki or Yamaha four stroke, awesome power & top end is good as well. Not sure but I'm guessing 40-45 MPH, plently for that hull, especially if you have multiple users. I worry overpowering a boat & having a less experience driver get it to dangerous speeds trimmed out in rough water.
blacksmithdog posted 07-10-2012 07:36 AM ET (US)
My 1992 15' GLS with a 2009 Yamaha F50 does 34 mph at 5500 rpms (WOT) with two adults and 12 gallons of gas, after playing with the trim awhile. I'm running a Yamaha SS 10-1/2" X 12" prop. This is from the GPS.
skred posted 07-12-2012 10:53 AM ET (US)
My former 15 Sport Center Console (1986), ran 35-38 mph per GPS with my 50 hp Merc 4-stroke. I had sold the Yamaha 70 that was on it when I bought it, and only lost about 3-4 mph with the 50. I believe it was a perfect match for the boat. I called the 70 Yamaha "scary fast"....

blacksmithdog posted 07-14-2012 04:59 PM ET (US)
I might need to look into a new prop. But, whoever mounted this engine used the deadly "blind" mounting method, so it may be a tish too low.
Tom W Clark posted 07-14-2012 08:47 PM ET (US)
If the blind holes were used it is 2-1/4" too low, not a "tish".
It's an easy fix though. Just fill the blind holes through the transom and drill two new one on the BIA standard lateral spacing but make them 6-1/2" below the top bolt hole instead of 8" below the top bolt holes. This will allow the motor to be bolted on "Three Holes Up".
sosmerc posted 07-21-2012 12:36 AM ET (US)
My 1984 15 center console/1996 F50hp Merc is now running 39mph with just me and 9 gallons of gas and 4hp kicker motor.
I think that 50hp is a good match and a well balanced rig.
The fuel economy is awesome. (15 pitch stainless Silverado @6200 rpm max) 20-21 mph @ 3800 RPM.
I love this little boat.
protek9543 posted 07-21-2012 03:43 PM ET (US)
I have a 1979 15' converted to a Supersport. I run a Mercury 70hp and it will fly. I have pulled two tubes with 5 teenage boys with no problem.
Binkster posted 07-22-2012 12:22 PM ET (US)
How will a 15 footer run with a 50 and maximum capacity 5 person load. Not too well I would think.
rich
sosmerc posted 07-22-2012 07:59 PM ET (US)
Depends upon which 50hp we are talking about. My guess is that a "bigfoot" 50 EFI Merc would do pretty well pushing a 15 with a good load aboard. On the other hand, a conventional 2 stroke 50hp with a 2:1 gear ratio might be struggling a bit.
BUT, in either case, the engine would need to be propped to be capable of achieving max rpm with the load aboard. A much smaller pitch prop would be required to plane a heavy load...and as a result, top speed would drop considerably.
The current model 15 might do a bit better with a heavy load, as it appears to be wider and as well as a hull with less deadrise.....but the classic 15 probably handles rougher water somewhat better.
dgoodhue posted 07-23-2012 10:43 AM ET (US)
I would think a classic 15' w/50 hp would handle 5 people and have no problem planning and would still have adequate performance. A 50 on a 15' has similar performance to a 13 w/40 hp.
I am sure some else with more experience can chime as my experience is with 60&70's but I suspect that 50hp would have adequate performance.
blacksmithdog posted 07-26-2012 06:24 AM ET (US)
With 4 adults and gear mine will only do in the high 20's.
saxart posted 07-30-2012 10:25 AM ET (US)
I have owned two 15' Whalers and may have an interesting perspective on this question.
The first boat was fitted with a 70hp two-stroke. That boat was WAY over powered. As a teenage boy, it was a real thrill to run, but even then I recognized the chine-walking condition this size motor can produces is just short of an accident waiting to happen. If I remember correctly, there is some documentaion from Whaler (maybe the owner's manual) that suggests that this set up needs to be run with caution.
I currently run a vintage 15' Sport with a 50hp Yamaha 4-stroke. That motor is PLENTY of power to pop up a skier and will still make my 13 year old daughter turn around with a big grin when we open it up for a quick run across the lake. Again, PLENTY of power for almost all needs.
In my opinion a vintage 15 with a 90hp is pure lunacy.

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Author	Topic: Classic 15-footer with 50-HP
LKD	posted 03-01-2011 07:19 PM ET (US) I know the classic 15-foot Boston Whaler boat is rated for a maximum 70-HP engine, but is a 50-HP Yamaha considered to be adequate power for this hull? I value and appreciate all responses. Thanks--Keith
Russ 13	posted 03-01-2011 07:26 PM ET (US) It depends what your primary use of the boat will be. For general use, with two to three passengers, yes the 50-HP will be fine. If you want to waterski and pull inflateables then 70-HP or 90-HP would be the way to go. I have a 90-HP on a 1989 hull that is SUPER, but I use the boat to tow wakeboards and tubes. The 15-footer is a great little boat.
Jeff	posted 03-01-2011 07:44 PM ET (US) Growing up we had a Super Sport 15 with a four-cylinder Mercury 75-HP on it. The boat was beyond what would be considered safely powered. It was a rocket that needed your utmost attention at speeds above 35-MPH as the hull had a real tendency to chine walk. It would top out with just me at speeds in the 50-MPH range, which was way too fast. That ended up being the reason my father sold it. Nonetheless, if I had one today I would prefer it to be powered with a 50-HP or may 60-HP motor. I honestly think that is enough power for that hull even if you are wanting to do water sports with it. This is coming from a guy who usually advocates for powering beyond the recommended max.
BobL	posted 03-01-2011 10:02 PM ET (US) Keith--I have a 1987 Super Sport 15 with a two-cycle Yamaha 50-HP. I think that a 50-HP outboard is plenty for the boat. It is fast, pops up on plane quickly, and top speed is as fast as I need. My wife and I usually just use the boat for cruising around. Part of what makes this combination handle so well is the lightweight engine. With power tilt and trim it weighs about 165-lbs. Unless you plan to really load up the boat and use it for water sport, I think you will be happy with the performance and economy of a 50. BobL
pcrussell50	posted 03-01-2011 11:03 PM ET (US) I have the max power engine option on my Sport 13, 40-HP and it accelerates like a R-O-C-K-E-T-S-H-I-P. I can't even come close to full throttle in the ocean. I say, if you're an ocean boater, you'll be fine with the 50. If you will have access to smooth water and want to be a fast boater, you'll want the 70, because you'll be able to get well into the upper 40's if you rig right and don't put too much heavy stuff. It's probably the "fastest" hull in the Whaler lineup. -Perer
andrey320	posted 03-01-2011 11:26 PM ET (US) I agree with Peter. I've got a 50 Honda on my Dauntless 15 and it is not a fast boat by any means, but I can't go over 25mph for long most of the time anyway. My boat tops out at a bit over 30mph. The Dauntless is a much heavier hull too, so a sport would go several miles faster than that. My boat with a few people on board pulls me (160 lbs) out of the water on a wakeboard with ease.
kwik_wurk	posted 03-02-2011 12:57 AM ET (US) For average use, a 15 with 50-HP would be great. Inner tubing would be fine, even wake boarding. But, I wouldn't water ski behind it. - And if you have kids it's not overpowered. A 15 with a 90 Mercury is a rocket ride. My friends had one in high school and we could pop wheelies and jump freighter wakes--way overpowered for our level of common sense. And it would yank you right out water skiing. However the boat is a little light and you could really pull it around when cutting hard. The only thing we didn't like was the boat sat a little squat in the back with the over sized engine.
pcrussell50	posted 03-02-2011 02:31 AM ET (US) quote: The only thing we didn't like was the boat sat a little squat in the back with the over sized engine. Like pretty much all fast, outboard powered, v-hull boats. -Peter
Peter	posted 03-02-2011 06:51 AM ET (US) A 50 HP outboard on a classic 15 Whaler should be able to push it to 36-37 MPH, which is pretty fast. A 70 will push it to at least 42 MPH. Over 39 MPH the boat has a tendency to chine walk and requires more concentration in driving it.
jimh	posted 03-02-2011 07:46 AM ET (US) [Moved to PERFORMANCE.]
jimh	posted 03-02-2011 08:02 AM ET (US) I had a SPORT 15 with a 50-HP Mercury. It would hit about 35-MPH at full throttle. It was a very fun and responsive boat.
elaelap	posted 03-02-2011 09:23 AM ET (US) My Yamaha F60 pushed my Sport 15 center console along at ~42 mph with only me aboard. Don't know about waterskiing or wakeboarding, though...never had the pleasure. http://continuouswave.com/ubb/Forum1/HTML/018267.html Tuco
weekendwarrior	posted 03-02-2011 10:02 AM ET (US) I have a 50HP Honda on my Montauk 17' and it's fine. Top speed just a tad over 30mph, fine for wakeboarding even with 5 in the boat. Not really enough to pull a tube with any excitement but fine for dragging little kids around. I did pull a girl on a slolem (sp?) ski once, she got right up but I was pretty much full throttle to give her enough speed and she didn't really do much in the way of tricks. So in short, 50HP is plenty practical for the 17 for most uses, I think it should do fine on a 15.
Tohsgib	posted 03-02-2011 10:20 AM ET (US) I have had a couple 15's and a 50 is plenty for most people and you can pull a skier with one. Mine did about 37mph which is flying when you are 9" above the water. You can also run all day on a 6 gal tank. For years I ran my 79 sport with a 1984 Johnson 60 which would run a 19" SST @6k through a 2.4:1 which is the same as the 70...she flew but way before the GPS days.
dgoodhue	posted 03-02-2011 10:24 AM ET (US) If setup properly you should see top speed of around 36mph or not all that much different than a max hp classic 13. I would guess it will be a touch slower on acceleration than the max hp 13' because of the extra weight of the hull.
dgoodhue	posted 03-02-2011 10:27 AM ET (US) quote: It's probably the "fastest" hull in the Whaler lineup. It's one of the faster small Whaler hulls.
Peter	posted 03-02-2011 11:24 AM ET (US) I think the classic 15 hull is faster than the classic 13 hull. The 13 has a hook in the hull and drags skegs through the water, the 15 does not. It would not surprise me in the least to find out that the 15 goes faster with a 40 HP motor than the 13 does.
pcrussell50	posted 03-02-2011 11:49 AM ET (US) quote: It's one of the faster small Whaler hulls. I put "fastest" in quotes, because I was using the word to refer to the hull bottom shape, not necessarily the top speed attained. The 15's bottom looks almost like a proper performance boat, minus the pad. -Peter
Tohsgib	posted 03-02-2011 12:02 PM ET (US) Been discussed before and I belive the 15 is the fastest Whaler in proportion to size. The 15 is just as fast if not faster than a 13 with comparable power and hence why the new 130 Sport does so well even weighing more than a classic 15.
mkelly	posted 07-10-2012 12:02 AM ET (US) I realize this thread is old & may not be read....but I recently repowered my 1986 15' center console sport (I think that's the model) with a 60 HP Yamaha 4-stroke...it is awesome! Highly recommend the Suzuki or Yamaha four stroke, awesome power & top end is good as well. Not sure but I'm guessing 40-45 MPH, plently for that hull, especially if you have multiple users. I worry overpowering a boat & having a less experience driver get it to dangerous speeds trimmed out in rough water.
blacksmithdog	posted 07-10-2012 07:36 AM ET (US) My 1992 15' GLS with a 2009 Yamaha F50 does 34 mph at 5500 rpms (WOT) with two adults and 12 gallons of gas, after playing with the trim awhile. I'm running a Yamaha SS 10-1/2" X 12" prop. This is from the GPS.
skred	posted 07-12-2012 10:53 AM ET (US) My former 15 Sport Center Console (1986), ran 35-38 mph per GPS with my 50 hp Merc 4-stroke. I had sold the Yamaha 70 that was on it when I bought it, and only lost about 3-4 mph with the 50. I believe it was a perfect match for the boat. I called the 70 Yamaha "scary fast"....
blacksmithdog	posted 07-14-2012 04:59 PM ET (US) I might need to look into a new prop. But, whoever mounted this engine used the deadly "blind" mounting method, so it may be a tish too low.
Tom W Clark	posted 07-14-2012 08:47 PM ET (US) If the blind holes were used it is 2-1/4" too low, not a "tish". It's an easy fix though. Just fill the blind holes through the transom and drill two new one on the BIA standard lateral spacing but make them 6-1/2" below the top bolt hole instead of 8" below the top bolt holes. This will allow the motor to be bolted on "Three Holes Up".
sosmerc	posted 07-21-2012 12:36 AM ET (US) My 1984 15 center console/1996 F50hp Merc is now running 39mph with just me and 9 gallons of gas and 4hp kicker motor. I think that 50hp is a good match and a well balanced rig. The fuel economy is awesome. (15 pitch stainless Silverado @6200 rpm max) 20-21 mph @ 3800 RPM. I love this little boat.
protek9543	posted 07-21-2012 03:43 PM ET (US) I have a 1979 15' converted to a Supersport. I run a Mercury 70hp and it will fly. I have pulled two tubes with 5 teenage boys with no problem.
Binkster	posted 07-22-2012 12:22 PM ET (US) How will a 15 footer run with a 50 and maximum capacity 5 person load. Not too well I would think. rich
sosmerc	posted 07-22-2012 07:59 PM ET (US) Depends upon which 50hp we are talking about. My guess is that a "bigfoot" 50 EFI Merc would do pretty well pushing a 15 with a good load aboard. On the other hand, a conventional 2 stroke 50hp with a 2:1 gear ratio might be struggling a bit. BUT, in either case, the engine would need to be propped to be capable of achieving max rpm with the load aboard. A much smaller pitch prop would be required to plane a heavy load...and as a result, top speed would drop considerably. The current model 15 might do a bit better with a heavy load, as it appears to be wider and as well as a hull with less deadrise.....but the classic 15 probably handles rougher water somewhat better.
dgoodhue	posted 07-23-2012 10:43 AM ET (US) I would think a classic 15' w/50 hp would handle 5 people and have no problem planning and would still have adequate performance. A 50 on a 15' has similar performance to a 13 w/40 hp. I am sure some else with more experience can chime as my experience is with 60&70's but I suspect that 50hp would have adequate performance.
blacksmithdog	posted 07-26-2012 06:24 AM ET (US) With 4 adults and gear mine will only do in the high 20's.
saxart	posted 07-30-2012 10:25 AM ET (US) I have owned two 15' Whalers and may have an interesting perspective on this question. The first boat was fitted with a 70hp two-stroke. That boat was WAY over powered. As a teenage boy, it was a real thrill to run, but even then I recognized the chine-walking condition this size motor can produces is just short of an accident waiting to happen. If I remember correctly, there is some documentaion from Whaler (maybe the owner's manual) that suggests that this set up needs to be run with caution. I currently run a vintage 15' Sport with a 50hp Yamaha 4-stroke. That motor is PLENTY of power to pop up a skier and will still make my 13 year old daughter turn around with a big grin when we open it up for a quick run across the lake. Again, PLENTY of power for almost all needs. In my opinion a vintage 15 with a 90hp is pure lunacy.